Telephone receiver



Nov; 3, 1925. 1,559,596

. J. A. WILLIAMS TELEPHONE RECEIVER Filed April 21, 1922 WIIIIIIIII/I/I/IIIIflI/Illlilllzrn 7/5 Patented Nov. 3, 1925.

' UNITED STATES 1,559,596 PATENT OFFICE.

.rosnrrr a. WILLIAMS, or CLEVELAND, onto.

TELEPHONE RECEIVER.

Application filed April 21, 1922. Serial No. 555,821.

nary wire telephone systems and is an im-' provement overrtlie construction constituting the subject matter of my prior application Serial No. 549,832, filed April 5, 1922. In my prior application referred to, Ihave disclosed a receiverwherein increased sensitiveness is obtained both by the provision of means whereby the permanent magnet flux is increased, and also by an arrangement wherein there is a larger available space for the coil, permitting a larger number of turns and greater ampere turns for a given current value, with the result that for even a .very feeble current a relatively large ampere turn value is obtained.

In said application the above objects were attained by utilizing a cup-shaped metal housing for the coil and its core, and by making use of the housing, core and diaphragm or part of said elements as perma nent magnets, the fields produced by the magnets assisting 'one another to produce an intense flux. By the use of these ele ments or part of them to produce a permanent magnet flux and by doing away with the permanent magnet which serves that function only, a feature ofcompactness is obtained to a high degree, andlthough the size of the receiver as a whole is small, there is a relatively large space permitted forv a. coil of many turns. Thus with a receiver of a small size, I amable tohimprpve all factors which bring about sensitivenessto minute electric currents in the reoeivercoil. The principal object of the present inven-. 'tion is to obtain still greater sensitiveness. for the amount of material employed in the receiver also to provide certain features .of construction wherein the housing and core, and if desired, :also the diaphragm may be used to greater advantage as permanent'ma ets. A further object is to so form the diaphragm that when vibrated it is capable of being flexed in a more uniorm manne'i' than with an ordinary diaphragm, and so that itwill give vibrations of greater amplitude for a given change in the flux and thus produce stronger sound waves for given ampere turns in the coil.

Inthe accompanying sheet of drawings wherein I have shown an embodiment of the invention which operates very effectively, Fig. 1 is a vertical sectional view of a receiver embodying my invention; Fig. 2 is a transverse sectional view of the same;

Fig. 3 is a vertical sectional view of thecup-shaped housing detached; Fig. 4 is a similar view of the cup of which the housing is formed, showing how the metal may beremoved to form-the final desired shape; Figs. 5 and 6 are transverse sectional views on an enlarged scale through a diaphragm formed in accordance with my invention,

,Fig. 6 showing a slight .modification over the construction shown in Fig. 4; and Fig. 7 is a face view of the diaphragm.

Referring to the drawingsfit will be observed that the receiver here illustrated is of the same" general design as that constituting the'subject matter of my prior application. The construction herein illustrated includes a cup-shaped housing 10 which receives a coil 11 surrounding a centrally ar-.

ranged core 12 having at its upper end a slightly enlarged head 12 and having a reduced lower end 12" extending through an opening 10 at the center of the base of the housing 10 and secured in position by nuts 13, the nuts and -core serving also to clamp the coil to the base of the cup or housing, the

ends of the coil having theusu'al insulat-.

inq' disks 14.

ihe upper or open end the housin' in this instance a down-turned .flange threaded on the interior and screwed-down erably formed-separate from the housing onto any externally threaded ring 17, preffor a purpose tobe explained, and secured I thereto in a suitablemanner as by brazing- In this instance the housing 10 and. core 12 are preferably formed of good magnet steel and constitute the permanent magnets of the receiver, though as in the preced. ing case the vibratory diaphragm'may also be used as a permanent magnet.

- 2 the housing is shown as provided with insulating bushings 18 through which the terminals are designed to be extended.

One important feature of the present invention resides in the special shape of the cup or distribution of the metal of which the cup 10 is formed. In this instance the metal is not of uniform thickness in the base and cylindrical wall of the housing as in my Though I do not desire to be confined to anyv articular proportions or thickness of meta at any given point, the thickness of the metal at one point relative to the thickness at any other is such that I obtain uniform flux carrying capacity in all parts of the base of the cup and in the cylindricalv wall of the cup. That is to say, the area of any circular section of the base from the central part to its periphery is substantially the same and substantially the same as the crosssectional area of the cylindrical wall of the housing. By decreasing the. thickness of the base from the central part outward and making the thickness of the cylindrical wall the same as the thickness of the periphery of the base, the metal of the housing irrespective of where the section is taken has the same fluxmarrying capacity this being of very great importance for the reason-that in this case as in my prior application the one magnetic pole of the housing is at the open top and the opposite pole is at the center of the base.

Another condition that I prefer to bring about'in the present construction is a .certain relation in the cross-section of the core; and the cross-section of the housing at any point so long as the cross-section is taken at right angles to the course of the flux threading through it. That condition orrelation is equality of the cross-sectional areas so that the core and cup or housing will have the same flTix carrying capacity.

As before stated, both the core and housing are permanent magnets and both are preferably formed of good magnet steel commonly employed in making permanent magnets for high grade instruments, and after the core and coil are formed of the proper shape and size .'the'"core can be set into the center of the housing and clamped in place,

and both can be simultaneously magnetized the same amount. This condition not only avoids an unnecessary amount of metal in one part or the other, but enables both magnets to be used effectively, one-in. conjunction with the other in' the production of fields which assist one another, but also the initial-magnetism is more eifectively maintained than would otherwise. be the case;

In forming this housing it may be initially of the same thickness throughout as shown by dotted lines in Fig. 4, in which event the cylindrical wall is turned or ground down to the desired final thickness, and the base is then tapered ofi' by cutting or grinding so as to leave the right distribution of metal to produce the results above stated. This is, of course, done before the steel is hardened preparatory to the magnetizing step.

- It is because the steel of which the cupis formd is hardened to an exceedingly high degree that the threads which receive the threads of the cap 16 when the latter is screwed in place are formed in a' separate ring. This ring is preferably formed of iron or machinery steel, low in carbon, so that it can be readily machined after the housing itself has been hardened. Generally the ring 17 is brazed to the cup or housing 10, and this can be done by copperplating the cup and also the ring, the copper applied during the plating serving as the brazing material to permanently fasten thering to the cup. After the hardening process the, threads then can becut on the ring, it being desired that they be cut subsequent to the hardening process so as to avoid distortion decreases from thecentral part or part oposite the core toward the peripheral part which is clamped between the cup and the top or open end of the housing where a thickened rim portion 15" is provided for clamping purposes. In forming this diaas in forming the-base of the cup, that is to .say, the cross-sectional area of any c rcular section with the center of the diaas the cross-sectional area of every other seetion, irrespective of where the sect on is taken, from that portion which is directly hra m the same condition is maintained phragm as an axis is substantially the same opposite the core indicated by the dotted circle of Fig. 6 to the thickened rim portion 15 In producing this diaphragm a fiat disk is'utilized of uniform thickness fronrthe oneside only as shown in Fig. 1 and center to the periphery, and then'one or both faces are ground or cut down, producing a diaphragm of gradually decreasing thick-' ness from the central part outward. This diaphragm may be cut or ground down on 5, in which event'one side,ggenerally the tion between .the central part opposite the core and the periphery where it clamped in place as alreadyv explained, and furthermore, a uniform flexing is obtained when the diaphragm is vibrated, the flexing being substantially uniformly distributed from the periphery where itis clamped in place to the region ofthe center. In other words, the flexibility is that of a relatively thin diaphragm of uniform thickness, but at the same time there is sufficient metal opposite the core to carry a relatively large amount of flux, and therefore suificient metal to enable vibration of large amplitude'for a given change in the value of the current passing through the receiver coil;

Though the diaphragm "may be in the form of a permanent magnet and may therefore be formed of good magnet steel as is .utilized in forming the core'and housing,

I prefer that it be formed of soft iron which has greater permeability than magnet steel,

and therefore for a given cross-section has greater flux carrying capacity.

I Thus it will be seen that the improve ments of this construction over that shown in my prior application are mainly of twofold nature consisting first of a coil housing preferably in the form of a permanent magnet and formed so as to have uniform ."flux carrying capacity in the cylindrical part and in the base, with the flux carry ing capacity of the core and cup or housing substantially the same, and secondly, in

the provision of a vibratory diaphragm which may be formed of magnet steel or soft iron, preferably the latter. which is of gradually decreasing thickness from the cenhousing having a central core extending tral portion opposite thecore to the-peing and cap.

the same."

ripheral clamping portion, and has substantially equal flux carrying capacity from the region of the center outwardly to the portion which is clamped between the hous- By these improvements above mentioned, the .sensitiveness of the receiver to very feeble. currents in the receiver coil is increased.

The above novel features are capable of conjoint use and to an extent may be used advantageously independently of each other.- For example, it may be desirable to form .the core 12 of soft iron instead of magnet Likewise my improved diaphragm 15 1 steel. may be used advantageously with other forms of receiyei's, and is 'not necessarily confined to one of the general type herein illustrated. Other changes may be made, and I aim in my claims to cover all modifications which do not involve a departure from the spirit and scope of my invention as defined in the appended claims.

Having described my invention, I claim:

1. A telephone receiver comprising a coil, a cup-shaped housing enclosing the coil and adapted to'convey flux through the base and upright portion thereof,'the flux carrying capacity of the base being substantially the same from the region of the center to the periphery.

2. A telephone receiver comprising a coil, a housing receiving the coil and having base and upright portions, a diaphragm at the open end of the housing, the flux carrying capacity of the housing through different portions of the base ,and through the up-' right portions being substantially the same. 3. A telephone receiver comprising a coil,

a metal housing containing the 'coil and a vibratory diaphragm opposite the coil, said housing having a base portion which decreases in thickness from the ccntralpart toward the periphery.

4. A telephone receiver comprising a coil having a core, a cup-shaped metal housing receiving the coil and a vibratory diaphragm opposite the coil and core, the base of the housing being thickest adjacent the centerand decreasing in thickness toward the periphery, and the upright 'wall of the housing having substantially the thickness of the peripheral portion of the base.

- 5. A telephone receiver comprising a coil having a core, a metal housing receiving the same and a vibratory diaphragm at the end of the coil and a portion extending up about the side of the coil, the area of annular sections of the base portion at different distances' from the center being substantially 6. In a telephone receiver, a metal coil pacity.

7. In a telephone receiver, a cup-shaped metal coil housing having a core extending from the base, the core and the base and up right portion of the housing having substantially the same flux carrying capacity.

8. In a telephone receiver, a cup-shaped metal housing for the receiver coil, said housing being a permanent magnet with one pole adjacent the center of the base and the opposite pole at the open end of the housing, the base of the housing being of decreasing thickness from the central portion outward.

9. In a telephone receiver, a cup-shaped metal housing for the receiver coil, said housing being a permanent magnet with one pole adjacent the center of the base and the .opposite pole at the open end of the housing, the flux carrying capacity of the housing from one pole to the other being substantially uniform.

Gil

10. A telephone receiver comprising a coil, a metal housing containing the coil and a vibratory diaphragm opposite the 0011, said 1 housing being. in the form of a permanent magnet and having a base portion which decreases in thickness from the central portion toward the periphery.

11. A telephone receiver comprising a coil having a core, a cup-shaped housing in the form of a permanent magnet receiving the 85 coil and'a vibratory diaphragm opposite the coil and core, the base of the housing being thickest adjacent the center and decreasing in thickness toward the periphery, and the upright wall of the housing having substantially the thickness of the of the base.

peripheral portion 12. telephone receiver comprising a coil having a core, aometal housing in the form of a permanent magnet receiving the same and avibratory diaphragm at the end of the housing opposite the coil and core, the housing having a base portion at one end of the coil and a portion extending up about the side of the coil, the area of annular sections of the base portion at different distances from the center being substantially the same as the cross-sectional area of the upstanding portion.

13. In a telephone receiver, a metal housing having a. base with an'upstanding core and having an outer wall, a coil within the housing and a diaphragm at the open end of the housing, the housing and core being formedbf permanent magnet steel, and said core base andouter wall having substantially uniform flux carrying capacity.

14'. A vibratory diaphragm for a telephone receiver having substantially the same flux carrying capacity adjacent its periphery as in the region of the center.

*15. A vibratory diaphragm for a telephone receiver formed so that annular sections cut on different radii are of substantially the same cross sectional area.-

16. telephone receiver comprising a cuplike housing containing a coil and a core, and a flexible metal dlaphragm closing the v end of the cup, the diaphragm having substantially the same magnetic flux carrying capacity from the central part opposite the core to the peripheral part adjacent the edge of the housing.

In testimony whereof, I hereunto affix my signature.

JOSEPH A. WILLI MS. 

